Telephone-exchange system



Dec. l, 1925. I 1,563.59'

J. N. WALTERS l A'III.I.|EIIIONE EXCHANGE SYSTEM Filed Sept. 19. 1925 6 Sheets-.Sheet 1 Iii- Dee. l, 1925.

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J. N. WALTERS TELEPHONE EXCHANGE SYSTEM Filed Sept. 19. 1923 6 Sheets-Sheet 5 /venbn- James-Al Wal/ers Rw www www s.

6 Sheets-Sheet 6 J. N. wALTERs Filed Sept. 19. 1923 TELEPHONE EXCHANGE SYSTEM L damesNll/Vd//ers Affi..

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Patented Dec. 1,1925.

,unirse srATEs PATENT oFFlcE.

JAMES N. WALTERS, OF EAST ORANGE, NEW JERSEY, -ASSGNOR TO AMERICAN TELE- PHONE'AND' TELEGRAPH COMPANY, A. CORPORATION OIF NEW YORK.

reunions-EXCHANGE SYSTEM.

implication mea september 19, 1923. serial No. 663,663.

To all whom t may concern.'

Be it known that l, JAMES N. 7vVAL'rnns, residing at East Orange, in the county of' Essex and State ot New Jersey, have invent- `ed certain Improvements in Telephone-EX- change Systen'is, ot which the following is a speciication.

This invention relates to telephone exchange systems and more particularly to systems in which machine switching equipment is employed tor establishing connections Vbetween subscribers lines.

In some -systems of the above mentioned character, a centralo'tiice sender is employed which controls the selective movements of the mechanical switching equipment in accordance with the directory numbers of desired lines. The calling subscriber causes the numbers to beregistered on the registers of the sende-r -through the operation of an impulse sending dial. A plurality of central ottice senders common to a large number otl subscribers lines are provided and an idle one of these senders is selected for the use of a subscriber immediately following the removal of the subscribers receiver from its sivitchhook ,upon the initiation of a call.

lt', after initiating a call, the calling subscriber neglects .to vdial the number ot a desired line and still maintains the receiver otll the switchhook, apparatus in the sender is operated to allow a predetermined period of time for the subscriber to begin dialing. -Upon the termination ot this time period, `the calling subscribers line is automatically routed to a trouble desk and the sender is autoinatically released. This same operation would occur when the calling line or substation apparatus is out oiE order tothe extent t-hat the manipulation` ot the dial by the subscriber does not operate the registers in the sender. Uponthe automatic release of the sender and the association ot the calling line with a monitoring position ot the trouble desk, a signal is lighted to indicate to-the monitoring operator that such a line has been connected to her position. The .monitoring operator thereupon connects a 0 i talking circuit to the line to make such inif'estigation as is necessary. f

lt after initiating a call, a calling subscriber only partly dials the number oic a desired line and still maintains the receiver oify the switchhook, a predetermined period of time is allowed :tor the remaining numbers to be dialed and upon the termination ot this time period a signal individual to the oiice sender is operated at a sender monitors position on a trouble desk of the office switchboard. ln response to this signal, the monitoring operator first challenges the Icalling subscriber, over a jack associated With the sender, to determine from the calling subscriber, if `possible,'the cause Jfor the delay in establishing the connection. It no response is received from the calling subscriber or if the calling subscriber responds and it is apparent that the lcalling line is in trouble, it is then desirable to connect the calling` line with a trunlcircuit terminating 'at the trouble desk :t'or further observation and until'the trouble on a line is cleared and to release the sender so that it may revert to common use.

.Itis the object vof this invention to provide means to automatically restore the oftice sender and to route the calling subscribers line to an operator for observation, upon a delayed setting ofthe registers of said sender after a subscriber initiates a y call.

This object is attained by special control circuits which are governed .by a time counting device individual to the oftice sender. After a predetermined time interval a circuit is automatically established in such a manner that the solider' is rendered busy and the translator switch of the sender is given an arbitrary setting to cause the sender to route the connection trom the calling subscribers line, through the subscribers district selector, to a permanent signal trunk circuit `terminating on the trouble desk. The sender is then automatically released and a signal is lighted in the trouble desk to indicatesuch connection to the operator.

This and other features of the invention may be more readily seen by reference to the tollowing description considered in connection with the accompanying drawings in which:`

Figure 1 shows one of a group ot subscribers lines kterminating in a full inechanical loitice of the exchange, a diagrammatic illustration ot a rotary line switch individualto the subscribers line, a district selector .by means of which the calling subscriber mayextend connections into various finder individual to the link circuit in which the district selector terminates, a permanent signal trunk circuit terminating in the ter-l minal bank ot the district selector andy efitending to the trouble desk ot the otiice, and a diagrammatic representation ot an incoming selector, iinal selector and called line.

Fig. 2 shows talking and signaling apparatus associated with an otlice sender .for indicating to a monitoring operator ythe progress ot the senderin controlling the establishment of the connection, together with jacksby means ci which the operator may talk with the calling subscriber, orset the senderV for routing a connection` to the trouble desk directly through the district selector, and a portion of an operators cord circuit for use with such acks.

' Fig. 3 shows a portion oi' the control circuits of the otlice sender and a class switch tor altering the circuits oiz the senderin raccordance with the class ot the' call which is to he established.

Fig. l showsa portion or the 'circuits ot the sender comprising a stepping relay, a group ot counting relays and a sequence switch i'orcontrolling these circuits.

F ig. 5 shows the code registers ot' the sender which are set inV accordance with the first two code or oiliee designation digits dialed by the calling subscriber and a steering switch which successively associates the code registers and the numerical registers shown inFig. G with the dialing circuit extending tothe subscriber-s line.

Fig. G shows the translator switch which assumes a setting in accordance with the code set up upon the code registers oft Fig. 5 and which controls the setting of: the class switchl ot Fig. 3 and the routing olf the dcsired connection. The nui'nerical registers which are set by the calling subscriber in accordance with the numerical designation o't the desired line are also shown in this ligure.

Fig` 7 is a diagram showing the manner in which the sei/'eral sheets of the drawing should be arranged to show as much of a complete organization ot circuits as is necessary to disclose the invention. Y

The calling subscribers lin-e C is of the usual type provided with a transmitter, receiver and call bell and since it terminates in an automatic exchange, it is also equipped with an impulse sending dial S oit the usual type.

The subscribers line C terminates in'an individual line switch 100 of the well-known step-by-step type. ln order to simplify the drawing only the wipers of theiswitch have been indicated.y

The district selector 150 disclosed in Fig. 1 is ofthe general type shown in the patent to E. li. Craft and J.' N. Reynolds, 1,123,696, issued January 5, 1915. To simplify the drawing, only one of the live brush sets and a portion ot the corresponding terminal bank ot this switch have been disclosed. The incoming and iinal selectors 185 and 190 are of this same 'type but have been disclosed only diagrammatically herein. The sender finder SF ,'F ig. 1, the time measure switch M shown in Fig. 2 the register steering switch RS and code registers A and B, Fig. 5, and the numerical registers TH, H, 'l and U and the translator switch shown in Fig. 6, are of the well-known step-by-step type. lilith the exception ol the sender linder SF and the translator' TS, the wipers of these switches are restored by being advanced by their respective steppingniagnets forwardly to normal position. Finder switch SF and translator switch TS have no normal position, the wipers thereotl resting in Contact with the setting of bank terminals last employed by the switches.

For controlling the circuits associated with the district selector and the circuits ot' the oiiice sender, auxiliary switches are employed. yl`he Switches may be ot the type disclosedinthe patent to J'. N. Rev- 'nolds and (LF. Baldwin, 1,127,808, issued February 9, 1915, and known in the art as sequence switches. The permanent signal trunk shown in Fig. 1 and the monitoring operators cord circuit diagrammatically illustrated in Fig. Q are ot the type fully disclosed and described in the Patent No. 1,509,851 to Edward F. Trapp, issued Sept. 30, 199.4. The different Vpieces ot apparatus employed in illustrating the manner Vin which Vthe invention is to be practiced having now been briefly described, it is thought that a clearer understanding ot the invention may be had from a description ot the manner in which a calling line may be connected tothe trouble desk.

Initiation of a call by the culling subscriber.

1t will'lirst be assumed that the calling subscriber removes his receiver 'trom its switchhook :and properly dials a desired number and that the connection is completely established in the usual manner. Upon the removal'oi the receiver trom its switchhook, a starting circuit is established `tor the line switch 100 in the manner vfully set forth in the Patent No. 1,505,171 to F. A. Stearn, issued August 19, 192i, and switch 100 starts hunting for an idle link circuit. The test terminals or" busy link circuits are rendered busy by ground potential on the multiples oi? the test terminals 114: ot such link circuits.V rlhis ground potential is connected thereto through armature contacts ot sleeve relays corresponding to relay 101, or through the contacts of sequence 'switch cams corresponding to cam 115. As soon as the test wiper ot switch 100 encounters the test terminal 1111 oi an idle link circuit,

will be encountered and the line switch 100 will stop with its wipers in engagement with the bank terminals connected to ksuch idle trunk. Battery potential is connected tothe test conductor 1111 through the lett-hand armature and normal contact ot relay 101 and the contacts ot' cani 113 Upon the seizure oit the link circuit terininating in the district selector 150, a circuit is established for sleeve relay 101 of the link, which may be traced 'from battery through the winding ot .relay 101, the normally closed contacts associated with the lett-hand armature of relay 102, the lower contact ot cam 103 (1 to 21/2), bank terminal 104C and wiper 105 or' line switch 100 and to ground through 4the winding of Cutbtl" relay 106. Relay 101 energizes in this circuit and establishes a circuit tor linerelay 107 of the district selector 150, which circuit extends -from battery through the right- `hand winding ot relay 107, the lower contact ot cani 108 (1) lthe lower contacts ot' -cain`109 and to ground through. the righthand armature and alternate contact oit' relay 101 andthe lower contact of cani 131 (17 to 15). At the alternate contact ot its letthand ari'nature, relay 101 connects ground potential `to the multiples ot test terminal 11.4l to mark the link circuit as busy to other line switches and 'at the normal contact of vthis armature disconnects thefsource ot' battery potential which up to the time the link circuit is seized marked the link4 as idle.

Relay 107, `upon energizing, closes a circuit Jfor driving sequence switch 100 out ot its normal. position 1, into'position 2, this circuit extending from battery through the magnet winding ot the switch, the upper lett-hand contact oit cani 111 (1), the inner right-hand armature and alternate Contact 'ot relay 107 and to ground at the righthandcontact ot cani 112 (1 to 6). Under the control ot master cain 180, the sequence switch is driven into position 2, in which position a circuit is closed from battery through the lett-hand winding of differential relay 102 and thence to ground at the upper lett-hand contact ot cain 115 (2 toy 11). Relay 102, upon'eiiergizing, closes a locking circuit tor sleeve relay 101 extending through the winding ot relay 101, the iuake contact of the lett-hand armature oic relay 102, the upper contact ot cani 103 (19x, to 10), and thence as previously traced from ground through the winding of cut?Y ott relay 106, this circuit being maintained tlirouglifposition 10 ot the sequence switch or until relay 102 becomes deenergized.k Vllpon reaching position 2, the sequence switch connects a new holding ground to test terminal 1111, through the upper rightluiud contact ot cam 115 (2 to 18%).

As soon as the sequence switch reaches position 1%, a circuit is closed tor the stepl ping magnet 116.01: the sender iinder SF extending from battery through the interrupter contacts and winding ot magnet 110, conductor 117 the lower lett-hand contact oft cam 118 (1% to 2), the inner right-hand armature and alternate contact oit relay 107 and thence to ground at the right-hand contact of' cani 112. t circuit is also closed at this time through the winding ot stepping inagnet'llt, the winding oit relay 1253 'and thence to ground at the lower lett-hand contact ot cam 115 (2 to 11).- Relay 123 does not energze at this time, however, since its winding is Vshunted by ground connected through the armature and contact of relay 107. As soon as the sequence switch 110 leaves position 1, the `initial energizing circuit ot relay 107 is opened at the lower Contact of cain 108, but this relay remains gize, opening at its inner right-hand armai ture and alternate contact the circuit eX tending through the stepping magnet 116 and closing at thenorinal contact of this armature, a circuit for driving sequence switch 110 out ot position 2 and into position 3. This circuit may be traced trom battery through the magnet winding of sequence switch 1.10, the upper right-hand contact of cain 111 the inner righthand armature and norinal contact of relay 107 and thenceto ground at the righthandcontact ot cam 112.

As soon as 'line relay 107 deenergizes, the shunt around the winding ol" relay 1.23 is removed at the innenright-hand armature and alternate contact of relay 107 and relay 123 energizes in series with stepping magnet 116, the currentflowing through this circuit, however, not being sutlicient to cause the energization of magnet 116. nt the normal contact ot its left-hand armature, relay 107 connects busy ground potential to the wiper 122, over conductor 121, the lower contact of cam 120, the upper lett-hand contact ot cam 110, the armature and contact ot relay `107 andv to ground through the lower contacts ot cani 112, which busy Yground potential is maintained untilvthe se.-

. Relay 502, upon ener out ot position 1, and under th J .1. and to battery through the Windingof relayY 302. "zing, closes a locking circuit for itself extending; throufh its inner right-lxand armature and alternate contact to conductor 300 independent ot the contacts ol cani 301 and :it its lett-hand ture and alternate contact esahlishes a ci cuit lor advancing class sequence switch 3l e inliuence o master calin 32 into positio o. 'this circuit nray be traced 'trein battery through the magnet Winding ot switch 306. the upper right-hand contact of cani 305 (1). conductors 304 and 3 3 and to ground at the righthand armature and noi-nml contact ot relay Relay 123, upon energizing, also establishes an irnpulsingl circuit exteinlinp` troni the calling' subscribers line to the controlling' relays oit the register steering;` switch 11H which niay be traced from battery through the Winding o'lt relay 307, conductor 200, conductor 308, wiper 163 of switch SF, conductor 164, conductor 165, the lelt-hand contact o1 cani 166, bank terminal 181 and wiper 182 of the line switch 100, thence over the calling` subscribers line loop and through the impulse mechanism S, Wiper 183 and bank terininal 184 of switch 100, the left-- hand contact ot'cani 160 (2 Vto 101/2), conductor 161, Wiper 162 of the switch SF, conductors 309 and 202 and to ground through the lett-hand winding` of coil 310. Relay 307 energizes in this circuit and cstablishcs a circuit 'tor the slow-to-release relay 312 extendingl troni battery through the Winding` of relay 312, conductor 311 and Vto ground at the armature contact of relay 307 and relay 312, upon energizing', establishes an obvious circuit for relay 313. lith relay 313 energized, the source of dialing tone 314 is inductively associated through the right-hand Winding of coil 310 with the irnpulsing circuit previously traced for transinitting adialing tone to the calling` subscriber to indicate to the subscriber that a sender has been associated With his line and is in readiness to receive impulses corresponding tothe number of the line desired. r1`his tone circuit may be traced troni ground through the secondary Winding of the tone coil 326, the right-hand Winding.;` ot coil 310, conductors 315 and 316, Wiper 500 and the normal terminal of bank A1 of code register A, conductors 501 and 502 and thence to Y ground at the lett-hand armature and nor- Lseasee the class sequence switch 306 moves out of position 1 and into position 3, a circuit is established for starting the tiine measure inechanisn'l at the monitoringl positron o1 the trouble desk to measure oli a time period su'licient to allow the calling subscriber to complete dialing. This starting circuit may be traced 'troni ground through the contact ci cani 321 to 1.8), conductors 320, 319, 318, 317, 213 and 212, the armature and norinal contact of relay 215, conductors 211, 210 and 200, Wiper 208 and the norrnal terininal ot bank M2 ot switch lvl, conductor 207, the slow speed interrupter 206. comm@ tors 205 and 204, and thence to battery through the winding olf relay Relay 203 energizes in this circuit as soon as rnterrupter 206 reaches a circuit closing position and closes a locking circuit for itselr ext-ending` from liiattery through its Winding', over conductor 214, through the Winding` of relay 215, conductor 216, the armature and contact of relay 203 and thence to conductor 212 and ground at the contact of cani 321 as previously traced. Relay 215 does not energize in this circuit until the interrupter 206 reaches an open position. llihen relay 215 does energize. a circuit is prepared for relay 217 which is effective as soon as interrupter 206 again reaches a circuit closing position. This circuit for relay 217 may be traced from battery through the Winding of relay 203, conductors 204 and 205, interrupter 206, conductor 207, the normal terminal of bank M2 and Wiper 208 of switch M, conductors 209, 210 and 211, the armature and alternate contact of relay 215, conductor 218, the Winding of relay 217, conductor 216 and thence to ground on conductor 212 through the ari'nature contact of relay 203. Relay 217, upon energizing,

closes a locking: circuit 'for itseltl extending' troni battery through the winding of relay 203, conductors 214 and 219, the left-hand armature and contact of relay 217, conductor 211, the armature and alternate contact of relay 215, conductor 218, the Winding oi relay 217, conductor 216, the armature and contact of relay 203 and thence to ground on conductor 212.

At its right-hand armature contact, relay 217 establishes a circuit for relay 222 which may be traced from battery through the Winding of relay 222, conductor 221, the inner right-hand armature and normal contact of relay 232, conductor 220, the righthand armature and contact of relay 217 and to ground on conductor 212. Relay 222 now establishes a .stepping circuitl for advancing the switch M under the infiuence of the slow interruptor 206 which may be traced from battery through the Winding ot stepping magnet 223, conductors 224 and 225, the lefthand armature and alternate contact of relay 222, conductor 205, interrupter 206. conduc.-

tor 207,;the strapped terminals 1 to `G ot bank M2 Wiper 208, conductor 20) jand thence to ground atthe alternate contact of the outer right-hand armature ot'l'elay lurinfzr the successive operation of relays 203, 215, 21T and 220 and the advance of the switch M from its normal position to position` 4 suhicient time is measured to enable the calling subscriber to dial a part ot thc desireiilnumber., .it at the time switch M reaches position 4, the number has not been partly dialed a circuit is automatically established to routethe calling` line to a trunk connectedto a monitoring operators position and to releasethe sender so that it m'ayreturn to its normal positionv for use in making` other` service connections. Y Signal lampi A167 in the monitoring' ope 'ators position, is now lighted from a circuit estab- "lish'edbyconnection of the calling' line to the trunk circuit. Upon ther lightingv oi lamp 167 the monitoring' operator 4challenges the calling' subscriber to obtain information regarding' any trouble that might existfin the v"dialing subscribers station and to give intion 4,no circuit will be established for re-` leasing' the sender and switch M advances to position 7. Suiiicient time has now. been V"measured to enable the 'calling subscriber to have completely dialed the desired number. It at the time the switch M reaches position 'i' the nuinberhas not been completely dialed, the switch M stops in position 7 since @its circuit is interruptedat the wiper 208 and a circuit is established tor thev sender lamp 225 which may be Vtraced `trom battery through the lamp 226, conductor 227, the Ne. T terminal, 228 of the bank M3, Wiper' 220,'conductors 230 and 231, conductor 508 and thence to ,ground at the arn'iature and alternate contact of relay 504. Relay 504 is energized at this time since a circuit was established through its Winding upon the energization of relay 313, Which circuit eX- A tends trom battery through the winding' of relay 504, conductor 505, the normal bank terminal ot bank RS1, Wiper 506, conductor 50iand thence to ground at the alternate' contact of the inner right-hand armature of relay It at the time switch M reaches position 7 the steeringy switch RS has leii't normal po-V sition, that is, a part of the desired line num- Vber has been registered and the sender' sequencesivitch 400 has not lett normal position, or is Waiting' for the completion 'of regristration in either positions 9 and 17, the lamp 223 will be lighted dimly throughv the windingI of relay 563 and the connection to position 1, the circuit 'for relay 563 may be traced trom ground at the inner right-hand armature of' relay 313, conductor 507, Wiper 6, the No. 1 terminal of bank RSI, conduc-A tor 4t2, the upper contact ofcam 470, conductor 471, the lett-hand Winding,` of relay 503, conductor 231 and thence to battery through the lamp 225 as previously traced. With sequence switch 400 in either position- 9 or 17 the 'circuit otrelay 563 may be traced from ground at the inner left-hand armature of' relay 313, over conductor565', the

vlower contact of ca1n470 and thence to bat-` tery through lamp 226 as previously traced.

It the register steering` switch RSv has moved ntl normal and the sender sequence switch is in any position other than posi-` tions` 9 `and 1?', the lanip 226 Will be Hashed over the Acircuit previously traced tothe armature and back contact of relay 563, conductor 508, the armature and normal contact of relay 504 and to `ground through the tast interrupter 513. In response to either' a brig'ht,'din1 or flashing signal on lamp 226, the operator at the monitors position challeng'es the calling' subscriber in a manner to be hereinafter described. It will first be assumed that the calling' subscriber proceeds within the required time interval to dial the digits of the desired number and that the calling subscriber desiring' a connection with a line Vwhose directory number is O A kland 3512 proceeds irst to dial the code letters O A to set the registers A and B,

Setting the code registers.

In response to the impulses transmitted by the sending' dial S, corresponding' to the code letter O, relay 30T is intermittently deenerg'ized and the Wipers of the code registerk A are advanced. six steps over a circuit which may be traced from battery, through the Winding of relay 503, conductor 512, the Winding;Y of stepping' magnet 511 of the register A, conductor 510` Wiper 509 and the normal terminal of the bank RSZ, conductor 323, conductor 322 and thence to ground, at the armature and back contact of stepping' relay307. Relay 503 is sloW-to-release and.

maintains its energization during; the transmission ot the series oit'y impulses through the Winding' of stepping magnet '511 and upon its initial energization opens at'its lefthandV armature contact the circuit 'previously traced over which dialing' tone Was transmitted tothe calling` suloscribers` line. During'the energizationot stepping' ymagnet 511 of the register A," relay 514 energizes in parallel Withthe Winding of relay 511 over a circuit which may betraced from battery through the Winding` of relay'514, conductor` 515, Wiper 516, the normal terminal of'bank RiSlead A, the oil-normal terminals of bank A2 of the A- register as soon as this register advances out of its normal position, conductor 518, the armature and contact of magnet 511, conductor 510, the normal terminal of bank RS2, Wiper 509 and thence to ground on conductor 323 at the armature and back contact of stepping relay 307. Relay 514 energizes in this circuit .and closes a locking circuit for itself independent of the armature contact of relay 307, which circuit Vextends over the circuit previously traced through the winding of relay 514, through the armature and back contact of magnet 511, conductor 323 and thence to ground at the right-hand armature and contact of relay 514. Relay 514 and stepping magnet 511 are thus maintained energized over this circuit until the stepping magnet 511 has moved its armature to substantially the full extent of its movement when the circuit through relay 514 is opened at the armature contact of magnet 511. Relay 514 thus insures that the stepping magnet 511 Will operate to the full extent of its movement upon each energization thereof. At its lefthand armature and front contact, relay 514 closes a circuit over conductor 519 for maintaining` the sloW-to-release relay 312 energized during each step of the register A irrespective of the operation vof stepping relay 307.

Upon the completion of the series of stepping impulses through the winding of magnet 5110i theregister A. relay 503 deenergizes and at its left-hand armature and normal contact establishes a circuit for relay 519, which may be traced from ground at the left-hand armature and back contact of relay 503, through the winding of relay 519, conductor 328, the upper left-hand and lower right-hand contacts of cam 327, conductors 523 and 607 wiper 606 and normal terminal of bank U1 of the units register U, conductor 605, Wiper 604 and normal terminal ot' bank T1 o1 the tens register T. conductor 603, wiper 602 and normal terminal of bank H1 of hundred register I-I, conductor 601, wiper 600 and normal torminal of bank TH1 of the thousands register TH, conductor 522, wiper 521 and the normal bank terminal of the bank B1 of the code register B, conductor 520, Wiper 517 and the oit-normal terminals of the bank A2 ort the code register A, lead A, Wiper 516 of the steering switch RS. conductor 515 and through the Windingof relay 514 to battery. At its outer left-hand armature and alternate contact relay 519 closes a circuit from ground, over conductor 528, through Wiper 527 in contact With the normal terminal ot bank RS", conductor 526, the righthand armature and back contact of relay 503, conductor 525 and thence to battery through the armature contact and Winding of stepping magnet 524 of the steering switch RS. Magnet 524 energizes in this circuit and advances the Wipers of the steering switch into Contact with the No. 1 terminals of the banks with Which they are associated, the circuit of magnet 524 being opened at the normal terminal of bank RS4 as soon as the steering switch leaves normal position.

lVith the steering switch RS in position 1, a circuit is established for the stepping magnet 530 ot. the code register B which may be traced from battery through the Winding of relay 503, conductor 512, Winding of magnet 530, conductor 529, the No. 1 terminal'of bank RSZ, Wiper 509, conductor 323, the outer left-hand armature and front contact of relay 313, conductor 322 and to ground at the armature and back contact of relay 307, and magnet 530 in response to the successive deenergizations of stepping relay 307 in accordance with the code letter A dialed by the calling subscriber advances the wipers of the code register B into position 2, Each time the impulsing circuit is established through the Winding of magnet 530, a circuit is established :tor relay 514 extending from battery through the Winding of relay 514, conductor 515. Wiper 516, the No. 1 terminal of bank RSS, lead B. the armature and back contact of magnet 530, conductor 529, and thence over the circuit previously traced to'ground at the armature and back contact of stepping relay307. In the manner previously described, relay 514 insures that the magnet 530 will be completely operated to cause the Wipers of register B to be advanced a full step upon each energizat-ion of magnet 530.

Following the completion of the second series ot code impulses, relay 503 deenergizes as previously described and again establishes thc circuit of relay 519 which may be traced over the circuit previously described to conductor 522 and thence through Wiper 521.r the olli-normal terminals oi bank B1 of code register B, lead B` the No. 1 terminal of bank RSS. wiper 516 and thence to battery through the winding ot relay 514. Relay 519, upon energizing, closes a circuit for advancing the register steeringswitch RS out, oit position 1, into position 2. The circuit of magnet 524 for advancing switch RS may be traced at this time trom battery through the winding and armature contacts `ot magnet 524, conductor 525, the right-hand armature and normal contact of relay 503, conductor 526, wiper 527, and the No. 1 bank terminal of the bank RS4. conductor 531 and thence to ground through the olif-normal terminals oi' bank B2 ot code register B and Wiper 532.

As soon as thc steering switch RS reaches position 2, a circuit is established for relay 533 which 'may be traced from battery through both windings ot relay 533, conductor 531, the No. 2terniinal ot bank R551, wiper 506, conductor 507 and thence to ground at the alternate contact of the inner right-hainl armature ot relay 313. llelay 533, upon energizing, locks through its righthand armature and alternate contact to ground at the contact otl cani 321, over conductors 319 and 320, and at the contact ot its inner lett-hand armature establishes a circuit lor advancing the translator switch rs, rig. e.

Setting tlm rrr/)relator Switch mi class' moito/L.

The circuit :tor advancing the t"anslator switch may be traced trom battery through the normally closed right-hand arn'iature contacts of relay 535, conductor 536, the arniature contacts and-winding ot stepping magnet 603 Ot the translator switch TS, conductors 609 and 537 and thence to ground at the inner left-hand armature contact ot relay 5334 The translator switch under the influence of stepping magnet 603 advances .its wipers until one of the test wipers 610 or 611 encounters a bank terminal upon which test potential has been placed through bank terminals and wipers of the code regH isters A and B, when a circuit is closed for relay 535. In the case assumed, code register A has been set in position 6 and the code register B has been set in position 2 and, therefore, the circuit of relay 535 may be traced from battery through the normally closed right-hand armature contacts and low resistance lett-hand,winding ot relay 535, conductor 533, wiper 539 and bank terminal 5110 ol bank A3 ot register A, conductor 541, wi per 5-1-2 and bank terminal ot bank B5 oit register B, conductor 544, test terminal 613 and test wiper 610 ot translator switch TS, the armature and normal contact ot switching relay 614 and thence to ground at the arlnature contact of relay 533, over conductors 609 and Relay 535, upon energizing in this circuitopens the operating circuit of stepping magnet 603 at its righthand armature contacts and removes the shunt from around its right-hand high resistance winding, so that relay 535 is maintained energized inthe circuit previously traced through both of its windings.

l-lad the first code letter been R. instead ot (i), then the code register A would be standing in position 7 and the switcl'iingl relay 61e would therefore be energized over a-circuit extending from battery through its winding, conductor 615, terminal 564 ot the bank if and to ground through wiper 541? and, therefore, the test wiper 611 would be employed for testing purposes rather than wiper 610. Banks B3, Bl and BG ot the code register B are cross connected to test terminals in the banks TS1 and TS2 oi the translator switch TS as desired 'to enable the translator switch to assume various positions correspondingto conibinatitms ot positions assumed by the ,ode registers A and l.

now set in 'the is the (l A kland otlice, or a mechanical office requiring the setting of the class switch into position T.

Upon the energization ot relay 535, a circuit is closed to advance the class switch 306 out oit position 3 which may be traced through the magnet winding et switch 306, the lower lett-hand contact ot cam 305 (3 to 15), conductor 330, the left-hand armature and normal contact ot' relay 329, conductor 331 and thencevto ground at the alternate contact of the outer lett-hand armature ot relay The class switch 306 continues to advance until class relay 329 becomes energized. Upon the class switch reaching a position Correspending` to the class setting ot the translator switch TS, it it be assumed that the switch TS has been set in position 4 for routing al call to the O A kland otiice, then when class switch 306 reaches position 6% a circuit is established tor relay 329 which may be traced troni battery through the winding of the relay, the upper letthand and lower right-hand contacts of cam 332, conductor 333, terminal 616 ot bank TS2 wiper 617, conductors 613 and thence -opens the circuit previously traced over conductor 213, whereupon relays 215 and 217 become deenergized and the counting o'tl 'time by switch M. is stopped. Upon the removal oi ground potential trom conductor 213, relay 232 beconies'energized in series with relay 222 over a circuit extending trom battery lthrough the winding ot relay 222, conductor 221, the winding ot relay 232, the, strapped bank terminals ot' bank M1 ot switch M, to ground at wiper 236i., it being assumed that wiper 234 has been advanced through the operation of stepping magnet 223 to some position between its normal position and position 7.

Upon the energization ot relay 232, a restoring circuit is established for the switch M which may be traced from battery through the winding ot stepping magnet 223,the armature contacts of this magnet,

'conductor 235, the inner lett-hand armature and cont-act of relay 232, conductor 236, the inner right-hand armature and contact ot relay 222, conductor 287, the strapped bank terminals oit bank M1 ot switch M and to `ground through wiper 23. As the wipers oi'f switch El pass position 7, the circuit of sender lamp 226 is maintained open at the outer right-hand armature and Contact of relay that the lamp 226 is not operated. Assoon as the wipers of switch M reach position 9. the circuits previously traced through the windings of relays 232 and stepping' niannet223 are opened and wiper 221- oit the switch Mis arrested with its wipers Standing' in position S. which position is a normal position 'tor the switch.

Remy 329. upon energizing'. also closes a circuit :tor advanc'no; the sequence switch 4100 ot the oiiice sender out of position 1 and into position 2 preparatory to controlling' the district selector in its brush selection movement. This circuit may be traced 'from battery through the magnet winding ot switch 400.` the upper right-hand Contact ot cam 4.01 (p1) i conductor 102` the lett-hand armature and alternate contact of relay 329, conductor 331 and thence to ground at the outer lett-hand armature and Contact et relay To insure the movement ot sequence switch 400 from one stoppingF position to another, the circuit o'l the magnet ot the switch is maintained over the master cam contact 403.

Setting the numerical registers.

Following' the dialina' ot the code letters ot the desired line designation` the calling subscriber dials the tour numerical digits. In response to the dialing' of the first thousands digit 3, the thousands register TH is advanced into position 3 throun'h the operation oit the stepping' magnet G19. The circuit ot stepping' magnet 619 may be traced trom battery through the winding ot relay 508, conductor 512, windingr of mao'net 619, conductor 020. the No. 2 terminal ot bank ,l-S2 and thence over the circuit previously traced to ground at the armature and back contact of stepping relay 307. During the transmission of each impulse through the winding' ot margriet 619, relay 514 is ener- 4q'ized over a` circuit extending' through its winding. conductor 515. wiper 516, the No. 2 terminal oit the bank RS? lead (l, the armature and back Contact ot stepping magnet 619, conductor 620 and thence to n'round over the circuit previously traced. Following the setting' ot the thousands register TH, the steering' switch RS advances into position preparatori7 to controlling; the setting' ot the hundreds refristerH.

In a simliar manner with steeringY switch RS in positions 3, 4 and 5, the hundreds. tens and units registers H. T and U are set by their respective stepping magnets 62.1. and 623 over conductors 624-, 625 and 626 respectively and the terminals of bank RS4 nets over leads D l'l and F, respectively, and

the Nos. 3, -1- and 5 terminals of banl lt ot the steering swit hv District brush selection.

lilith sequence switch 110 ot district sclector 150 in position I3 and the sender sequence switch in postion 2., a lfundaniental circuit is established extending from the oie- ;lice sender through the winding' ot the control relay 107 ot the district selector tor controlling the district selector in its brush selection n'iovement. This 'fundamental circuit inay be traced trom battery through the lett-hand winding ot relay 107, the upper' right-hand contact of' cam 119 the lower lett-hand contact ot cam 119 (3 to G), conductor "24.-, the inner right-hand armature and contact ot relay 123, wiper 125 ot sender finder switch SF, conductor 334, conductor 385, the contact ot. class switch cam (il to 131/2), conductor 337, the right-hand armature and back contact of relay 4:04, the lower right-hand contact of cani 405, conductor L100`r winding of sender stepping' relay 107, conductor 108, the armature and normal contact ot relay 409, conduct-or 410, the inner left-hand armature and back contact oi2 relay 4111, resistance element 412 and thence to ground through the left-hand contact of cam 4.18 Line relay 107 of the district selector and stepping' relay l107 ot the o'liice sender are ener- `g'ized in this circuit.

Relay 107, upon energizing', closes a circuit t'or driving sequence switch 110 ot the district selector out of position 3 and into position et. This circuit extends trom battery through the magnet winding' ot sequence switch 110 the upper left-hand contact ot cani 111 (3), the inner right-hand armature and front Contact of relay 107 and thence to ground at the right-hand contact ot cam 112 (1 to 0). lilith the district selector seqncnce switch 110 in position 4l, a circuit is now closed for the npdrive magnet 126 which extends trom battery through the winding' of magnet 126, the right-hand contact of cam 118 (4), the inner right-hand armature and tront contact ot relay 107 and to ground at the right-hand contact of cam 112. Magnet 126, upon energizing, presses the depending' portion ot switch shaft 127 against the constantly rotating' updrive drum 196, thereby causing the upward movement ot the 'switch shaft. Upon the movement ot sequence switch 110 out ot vposition the initial energizing circuit of relay 107 which extends through its lett-hand winding' and the upper right-hand contact of cam 119 is opened at the contact ot cam 119, but

lianclA arma-ture and front Contact andi to= the tundamental circuit previouslyV tracedI through the'lett-l'iandl contacts 'ot cam 119;

itsV the switch shaftt 127 approaches its first brusir selection position, the' shattlt' wiper` 12S` engages the hrst couductangV portion of commutat'or segment 120alnd a shunt' circuit is established around the Winding ot the sender stepping: .relay 407, which ina-y be traced from battery through the letLlnrndf nadir-1g, lett-hand. armature andi front' com` tact of relay 107', the upper ledit-hand conn tact .oit cam 119v (1 to; 6.),tliefufpper Contact of cant 120` (3,3/4A to 4),. con'ducto12`130, segment. 1,20; Wiper 128 and thence to! ground at'y thev righthand contact oi' cani lill (V9 to '11)1., rlelay 107 ismaintained energized overfthis i shunt circuit, but sender'stepping relay 40E iscausedV to decnergize; Als the switclr shaft' 112i? continues ine its upnmrd 1noaf'en'ient,the Wiper 128 engages an. insulatingy portion ot segment 129 f andi` the" shunt' circuit previously. traced is opened',` whereby lthe sendery step' V ping: relay 407 again energizes. 'llhhs,.diur

ing.; the upward movement o'tf therv switch; shatt, the sender stepping relay 407 is-interlnittently energized :rnd detenere/ized.

Under the assumption that the translator switch has been set into'y position 4,` a circuit is established'v upon the; first ene-ngization o stepping relay following the establishment' off the i'undamental circuit, which may be traced? froinbatterzy tlirouglrthe' No. 2 counting; relay 414, the armature and' nor; mail contact ofi the No; 2 counting.v relay 415, lead 416, Fig. G', terminal' 627? o'lfJ bank' 'PS3 ot the'translator switch,l Wiper 628', conducLv tor 629., class switchcam 339, con'ducto1j340", the upper left-hand contact of cam 417 (2), the lower right-hand contact off cam 4181 ('21), conductor 419, conductor 420,' the normally closed contacts l associated With:v the` outer lett-hancl armature of relay 4210,. the upper contact olii cani 422 (1` to 2), the" armature Contact oi" stepping relay 407, conductor 423 and thence to groufmlthrou'gh the uppery con tact oit ca1nf4113 (1 to Counting," relay 4114', upon energizing in thisy ci1.-cuit,cl'oses a loelingf circuit for itselfextending from bat tory' through; itsA Winding;- the` Winding of counting relay 415, the armaturey andv front contact. of ,relay 414, the; upper contact of cam 424? (2)"and1thenceto ground on con;- ductor 425. Counting relay 415i doesifnot energize, however,v until relay 407 deene-rgizes at the time the Wiper 128- lof the district selector engages' the irstco-nducting portion ofseginent 129; Upon the' energizatrio'nlof relay 415, the"l lead 416 isV extended through the' armature andl alternate contact of relay 4155, the arlnature and normal; contacto.' the No. 1l counting relay: 427 andjtlience'tozbat.- tery througlrtle Wind-ing. offt'l're"y No. count ing, relay; 426': UponI the secondi deenergiza tionf oli stepping' relayy 407:, relay 4272Y be;-v comes vdeenergized; andA connects lead 416';A to

the No. 0 counting: relay 42:8 and in responsefto itheznext deenergizatioir of stepping relay 407;,.the Noi 0 counting relay 429% isa energized; closing: ai circuit for driving sequenc'efswitch; 4001' outI of position 2 andi into position: 'lhlszcircuit mayI be tracedf from battery througlr the' Winding o4 sequence switch magnet 400, the lowerl right'hand contact ofi Camiel-,39 (-2)., theflei'it-hancl armae ture andi` normale' contact ofi relay. 486?, con ductor 440,. they inner right-hand armature: andnormal contact oct relayx 421', conductor' 441i and. thence to: ground at the armature and contaetof: theN'o 0 counting-Lrelay 429; Sequence' switch l400s upon leaving.: posi tion 2f openstthelocking-circuits of all count'- mgff'relays which lraveibeen locked up at the' right-hands'contactsoiicam 424 (2) .i At the time thcfN-b. 0" counting.: relay 429''en'ergizedf in'tresponsei tothef last deenergizationof stepping rei'afy 407', relay 409 isv energizedA in. parallel.therewith, opening at itsr armature and back Contact the previously traced fundamental circuit extendingl through the windings of stepping relay 407 and control relay 107? ofthe' district selector' 1150. As soon thereafter the Wiper 12SVv engages the next' insulating portiony of segment 129, the circuit orf relay IL'O'/is. opened and this rel'a-y deenergizesf, closing-fa circuit for driving the district selector sequence. switch 1110 out of positionat' and intoposition 5, this cirL cuit e'Xt'endiirgA from battery through` the magnet. Winding'oi sequence switch 110', the upper righthand contact of cam 111 (4), the inner right-hand armature and l'back con-tactof rel'a'a'f.` 107 an'dthencelto; ground at theright-hand.' contact' oi' can11'12. As soon as relay 10? deenergizes: the circuit preyif ously traced through thei upd-rive magnet 126 is opened attheAx inner right-hand armature and. iront contact, of relay 10'?y and the upward movement of thesWitcliY shaft' is arrest'ed. W'ith. sequence. switch 1:10 in position' 5 and the' sender sequence' switch 400 in position. 45, the fundamental circuit previously traced: ist` again established and relays 107 and again energize. Relay 107, upon energizing, causes the:movement of the district senueuiceil switchY 110,` from position 5 to.l position@ the' initial energtzingjclrcuitf of relay' 1.07, being'. opened' as previously describe'drat the@ upperrrigl1t-l1a11d .contact of ca1n11`f19as soon asfthez sequence switch leaves position 5 but relay lOTremaining energized overv the: fundamental circuiti. through it's left-hand windingi and the front Contact of its. letti-hand'. armature and `the leittlhand cont-acts of cami119; e soon as the-sender sequenceswitch 40.0 reaches` position 3,: a circuit is; established through therght-liandi Windin'glfio relay 102 at the district selector which may be traced from battery through the winding of relay 102, the upper right-hand contact of cam 146 (1 to 10), the outer right-hand armature and front contact of relay 123, the lower contact of cani 147 (3 to 10), wiper 148 of switch SF, conductor 341, conductors 342 and 343, resistance element 344, conductor 345 and thence to ground on conductor 425 through the upper contact of sender sequence switch cam 430 (4 to 18). Relay 102 is differentially wound, but due to the inclusion of resistance element 344 in the circuit of its right-hand winding the current owing through the right-hand winding is not suiieient to differentially release the relay. As soon as sequence switch 110 reaches position 4, relay 145 becomes energized over a branch of the'above traced circuit extending through the upper left-hand Contact of cam'146 `(4 to 10) through the winding of relay 145 to battery. Relay 145, upon energizing, prepares a circuit for energizing relay 107 when sequence switch 110 reaches position 9 as will be hereinafter described.

District group selection.

As soon as sequence switch 110 reaches position 6, the circuit previously traced for the updrive magnet 126 of the district selector is again established through the rightliand contact of cam 118 (6) and the inner right-hand armature and front contact of relay 107 and in the manner previously described switch sliaft 127 is again driven upwardly. Since at this time, however, the tripping spindle 136 has been rotated by the tripping magnet 135 which was energized in position 5 of sequence switch 110 over a circuit extending from battery through the winding of magnet 135 and the lower right-hand contact of cam (5 to 7), the third set of brushes is now tripped upon the initial upward increment of switch shaft 127 and during the continued upward movement of the shaft the brushes travel over the bank with which they are associated. The remaining four sets of brushes on the switch shaft are not tripped at this time and are, therefore, functionless. As the switch shaft approaches its first group selection position, wiper 132 engages the first metallic portion of the group selection segment 133 of the commutator and a circuit is closed in shunt of the winding of the sender stepping relay 407 which may be traced from battery through the left-hand winding, left-hand armature and front contact of relay 107, upper left-hand and lower righthand contacts of cani 119, conductor 134, segment 133, wiper 132 and thence to ground at the right-hand contact of cam 131 (9 to 7). Relay 107 is maintained energized over this circuit and the sender stepping relay 407 becomes deenergized. As the switch shaft continues in its upward movement and the wiper 132 engages the first insulating portion of segment 133, the shunt circuit is opened and sender stepping relay 407 again energizes. In this manner during the further movement of the switch shaft in its group selection movement, the sender stepping relay 407 is intermittently energized and deenergized.

Upon the first energization of the stepping relay 407 a circuit is closed for the No. 0 counting relay 428, it being assumed that the calling` subscriber has dialed such a code as to set the translator switch into position 4. This circuit may be traced from battery through the winding of relay 428, lead 431, lead 431, Fig. 6, terminal 630 of bank TS1 of the translator switch, wiper 631,` conductor 632, the contact of class switch cam 346, conductor 347, the upper right-hand contact of cam 417 (3 to 4), the lower right-hand contact of cam 418 (4), conductors 419 and 420, the lower Contact of cam 422 (3 to 4), the armature contact of relay 407, conductor 432 and thence to ground through the lower contact of cam 413 (3 to 4). Counting relay 428, upon energizing. closes a locking circuit for itself eXtending through the winding of the No. 0 counting relay 429, through the armature and front contact of relay 428 and thence to ground through the upper contact of cani 424 (4). Upon the first deenergization of Vstepping relay 407, relay 429 energizes in parallel with relay 409 and closes at its armature and front Contact a circuit for advancing sequence switch 400 out of position 4. This circuit may be traced from battery through the magnet winding of sequence switch 400, the contacts of cam 442, the left-hand armature and normal contact of relay 436, conductor 440, conductor 441 and thence to ground at the arinatnre contact of relay 429. Upon leaving position 4 the locking circuit extending through the windings of the counting` relays 428 and 429 is opened at the contact of cam 424 and these relays tlieieupon (lcenergize. Relay 409, upon energizing, opensI the fundamental circuit at its armature and back contact thereby causing the deenergization of line relay 107 of the district selector as soon as wiper 132 engages the next insulating portion of segment 133.

Relay 107, upon deenergizing, opens at its inner right-hand armature and front contact the previously traced circuit of the npdrive magnet 126 thereby arresting the upward movement of the switch shaft for positioning the tripped set of brushes on the first set of terminals of the first group of terminals of the bank. At its inner righthand armature and back` contact relay 107 closes the previously traced circuit for driv- Lacasse ing sequence switch 110 out of position 6 and. into position 7. In position 7, relay 107 energiz'es over a circuit extending from battery through its right-hand winding, the

` lowercontact of cam 108 (7 to 7%), the

`hand contact of cam 111 (7 the inner righthand ari'nature and alternate contact of; relay 107, the upper contact of cam 112 (i7 to 8) and thence toy ground at the righthand arn'nrtrufe and front contact of relary 102.

Tf/*zmt' intenti/)rg ait the elisir/025 selector.

.A soon sequence switch 110 leaves position 7 the initial energizing circuit of relay 107 is opened at the lower Contact of cam 108, hut relay 107 locks up over a cir-- cuit exten-ding from battery through its leftw hand winding and` left-hand armature `contact, the right-hand contacts of cam 188, the outer right-hand armature and front contact of relay 107. the lower contacts of cam 180 (7 to 8f) to the test brush 1410 and if the first trunk of the lsecond. gronpfishusy, to `ground at the test terminal of such busy trunk. Upon reaching position 8 with relay 107 energized, a circuit is established for the updrive magnet 128 which may he traced vfrom battery through the magnet 126, the-lower righthand contact of cam 118 the inner right-hand armature and front contact of relay 107 and thence to lgrouinl at the right-hand contact of cam 112. I The updrire maenet 120r upon energizing again drives the switch shaft upwardly in search of an idle trunk in the. selected group, So long as the test brush 1f-l-0 encounters the terminals of busy trunks, relay 107 remains locked up. lVhen.y however, an idle trunk is encountered which it will be assumed is the truuk terminating in terminals 186, 187 and 188 extending-` to an idle incoming selector 185, the locking circuit of relay 107 is opened and relay 107 deenergizes as soon as the brushes 150 andi-i0 have-been prop orly. centered on the bank terminals of thc selected trunk. Until the brushes are so centered, relay 107 remains lockedv up over a circuitY extending through its right-hand winding,y the upper Contact of cam 108 (8,), the brush centering segment 141e, shaft kwiper 1115-, theuinger, cont'aetofcanr118 (8)', the in,- ner right-hand arma-ture and front Contact ofv relay 107 andy thence to ground. at the rightdia-ndcontactof m1111112, Upon deenergizing, the circuit ofthe updrive magnet 120 is opened at the inner right-hand armature of relay 107 and the upward movement of the switch vshaft is thereby arrested and acircuit is closed at the inner right-hand armature and back contact oiy relay 107 for driving sequence switch 110 out of position 8 and into position 9. Upon reaching position 81/2, busy groundV potential is connected to the multiples of test terminal 188 of the selected trunk over brush 1&0 and the righthand contacts of cam 188.

Relay 111:5 being energized at this time as hereinbefore described, a circuit is established as soon as sequence switch 110 reaches position 9 for again energizing relay 107, which circuit may be traced from battery through the right-hand winding of relay 107, thelower contact of cam 108 (9 to 10) the lower right-hand and upper left-hand contacts of cam 109A and thence to ground atv the armature contact of relay 145x Relay 107 upon energizing inl this circuit closes zr circuit through its inner right-hand armature and front contact for advancing sequence switch 110 out of position 9 and into position 10, in which position the fundamental circuit is extendedV over conductors 12e and 158 and through contacts of cams and 157, through brushes 1:51 and 150, respectiyely, of the' district selector switch to the line relay (not shown) of the incoming selector switch 185.

1t will be assumed that the line of thedcsired subscriber may be reached without employing an ottico selector and that, there-A fore, the translator switch TS in position i establishes a circuit for advancing the sen der sequence switch i100 through positions (S- and 8 which are ordinarily employed for controlling the selective movements of office selectors, into position 10, in which position a fundamental circuit is established for controlling the selective nwrem'cnts of the in coming selector. TVhen, therefore, sequence switch L'100 leaves position 4i following the completion of district group selection and passes through positions to 51/1., a circuit is established for relay 1-88 which may be traced from battery through the winding.;l of relay 438, conductor 1184s. the upper left. hand contact of cam 118 to 5,1/1), the lower right-hand contact of cani -1-17 (Lig/jA to (i), conductor wiper 688, terminal 684- of bank T55 of the. translator switch, conductor 085 and thence to ground at the outer right-hand armature and hack contact of relay Relayk L188, upon energizing,

closes a locking circuit for itself extendingv through the lower left-hand contacto'f cam which locking circuit is maintained fenergized until sequence switch 400 lea-yes po'- sition 8. At its leftehand armature Vand contact relay 188 closes a lockingv circuit for counting relays 428 andi 429 which. may he traced from battery thr'iughwinding of relay 423, the winding of relay 429, conductor 443, the upper contact of cam 437 (5 to 3), the left-hand armature and contact of relay 433, conductor 433 and thence to ground through the upper contact of cam 333 (3 to 15). rEhe llo. 0 counting relay429 is thus maintained energized until sequence switch 400 leaves position 3 and at its armature and contact maintains the driving circuit of sequence switch 400 closed so that sequence switch 400 is driven into position 10.

Trini/t' test.

lVith sender sequence switch 400 in position 10 a fundamental circuit is closed through the winding of trunk test relay 349, Fig. 3, for testing the operative condition of the selected inter-oiiice trunk. This fundamental circuit may be traced in part from wiper 151 of selector 150, the righthand contacts of cam 149 (10), conductor 124, the inner right-hand armature and front contact of relay 123, wiper 125', conductor 334, conductor 335, resistance element 363, the contact of cam 343 (4 to 7), winding of relay 349, conductor 350, the Contact of cam 444 (9%A to 10), the outer left-hand armature and back contact of relay 411, conductor 351, conductor 352, wiper V159 of switch SF, conductor 153, the lower contacts of cam 157 and thence to brush 156. If the trunk tested is in proper operating condition, that is, has no open conductors, relay 349 energizes and at its armature contact closes a Acircuit over conductor 354 for energizing relay 433. Relay 433, upon energizing, closes a circuit'for advancing sequence switch 400 into position 11, which circuit may be traced from battery through the magnet winding of switch 400, conductor 445, the lower Contact of class switch cam (4 to 7), the lower contact of cam 437 10), the left-hand armature and contact of relay 433 and thence to ground over conductor 433 and the upper contact of cam 333 (3 to 15).

lllith sequence switch 400 in position 11 a local energizing circuit is established for relay 407 which may be traced from baittery, through the right-hand contact of cam 456 (11). conductor 406, windings of relay 407, conductor 403, the armature and back contact of relay 409, the inner left-hand armature and back contact of relay 41,1, resistance element 412 and thence to ground at the left-hand contact of cam 413 (11). lie- Vlay 407, upon energizing, closes a circuit for advancing sequence switch 400 into position 12 which may be traced from battery through the magnet winding of sequence switch 400, the lower left-hand contact of cam 429 (11), conductor 423, the armature and contact of relay 407, conductor 432 and thence to ground through the lower contact of cam 413 (11 to 12).

naa-sance Incoming brush selection.

lith sequenceA switch 400 in position 12 a fundamental circuit is established extending from the oiiice sender to the incoming selector switch which may be traced in part from brush 151 of the district selector over the circuit previously traced to conductor 335, the contact of cam 336, conductor 337, the left-hand winding of overflow relay 457, the left-hand armature and back Contact of relay 404, the lower contact of cam 456 (12 to 16), conductor 406, the windings of stepping relay 407, conductor 403, conductor 410, the inner left-hand armature and back contact of relay 411, the left-hand contacts of cam 453, conductor 351 and thence as previously traced to brush 156 of the district selector. The current flowing in this circuit is not in the proper direction to operate the polarized relay 457 but sender stepping relay 407, however, energizes in this circuit. Under the assumption that the numerical designation of the desired line is 3612 and that the calling subscriber has therefore set the thousands register TH into position 3, a circuit is now established for the ilo. 1 counting relay 426 extending from battery through the winding of relay 426, the armature and back contact of relay 427, lead 475, lead 475, Fig. 6, terminal 636 of bank THS, wiper 637, conductor 633, the upper contact of cam 446 (11 to 12), the lower right-hand contact of cam 413 (12), conductor 419 and thence over the circuit previously traced through the armature contact of relay 407 and to ground at the lower contact of cam 413 (11 to 12).

ln the well-known manner the counting relays are operated and locked up in succession during the brush selection movement of the incoming selector 135 until the No. 0 counting relay 429 is energized in parallel with relay 409, when the fundamental circuit is opened and a circuit is closed as previously traced for advancing sequence switch 400 into position 14. lVhen switch 400 leaves position 12, the locking circuits of the energized counting relays are opened at the contact of cam 424 (12).

Inco/111511() (/raup Selection.

illith sequence switch 400 in position 14 the fundamental circuit previously traced through the windings of sender stepping relay 407 is again closed. Relay 407, upon energizing, establishes a circuit for the No. 3 counting relay 447 it being assumed that the calling subscriber has set the hundreds register into position 6. The circuit of relay 447 may be traced from battery through the winding of relay 447, the armature and back contact of the No. 3 counting relay 449, lead 443, lead 443, Fig. 6, the outer armature and front Contact of relay 639, which relay waage is energized vat this time over `terininal 640 ,thegi'oup selection increment of the Lincoming select-or 185, the countingrelays operate yand lock up in ,successionuntil the JN0. `l counting relay 429 energizesin parallel With relay 409, when the fundamental circuit is openedto arrestthe selective inox/'ement of the incoming selector and .sequenceswitch 400 is1advanced in a inanner previously describedinto position 16.

Final brash Selection.

lWitli sequence switch 400 in `positiOn 16, the fundamental `circuit above 4traced -is again established through `the windings of sender stepping relay 407 and tvhe Winding oit `the 4control relay (not shown) yoi the tinalselector 190. Uponthe energization of relay 407 in this circuit, a circuit is establish'fed lior the No. 1 Acounting relay 426 which inay be traced from battery` through the. Winding otrelay 426, the arinatureand back contact of the No.1 countingrelay `42,7, lead 475, lead 645, Fig. 6, terminal-646 of the bank H3 ofthe hundreds register Il-I,

.Wiper 647, conductor 648, thev lower righthand contacts of cains 446 and .418 and thence through the arinature contactiotgrelay 407 to groi'ind at the lowerfcontactroi` cani 413` to 16). Relay 426 locks up in the wellflrnown man ner through the `Winding ot the upper No. lcountingrelay427 and duringl the brush selection rnoveinentz ,of the linal selector 190 the counting relays operate in succession until the No. 0 counting relay 429 energizes in parallel with relay 409,l

when the fundamentalcircuit is opened to `arrest the selectivenioveinent otselector 190 andthe circuit previously traced is Vestablished for advancing` sequence switch 400out o1 position 16 into position 17.

If; at the time sequence switch 400 reaches positioirl'? the calling subscriber has coinpleted dialing and `the register steering vswitch RS has ladvancedinto positionf), a `circuit is established etorvadvancing sender `sequence switch 400 out otposition 17 `into position 18, preparatory to2 controlling linal tens selection. This circuit `inay be traced troni ground at the innerright-hand arniature ofrelay 313, conductor507, Wiper 506,

terminal `5,48 ot banlvRSlgof switch RS,

conductor 549, the lower contact of class switch canr359 (4 to'7), conductor 360,.the lower lefthand contact yof cani 401 (17) and through the magnet Winding of sequence Switch Q`jtolbattyf ltV is torbenoted in Jhis connection that as s ooii'as the calling subscriber completed the dialing of the .units digit of the desired number, the steering switch RS was v'ad- .vaiiced in to position6, whereupon a circuit was'fcstablish'ed for advaneing'itinto posii i.. Y y tion 7, which inay be ,traced troni battery lthrough the Windingand varmature Contact of stepping magnet 524, conductors 52,5 and Wiper v527, .bank terminal 550 01" bank,

yRSSconductor 551, -the right-hand contacts` of classV switch cani 361, conductor 362, the contact 'ot cani 450, conductor 402, the lei":thand armature and front Contact ot relay` conductor Sland thence to ground at the arinature Contact ot relay `535. Upon reaching position 7 ,switch RS is advanced intoposition S over a similar circuit extending .through ythe Winding `of magnet 524, through u'iper 527, 'bank terminal V552, conductor 553, the ylower left-hand and lupper right-hand contacts yof cain 361, and thence over the circuitpijeifiously traced VtoA ground at the contact of relay 535 and the` switch is `further advancedinto position 9 over Wiper 527, terminal 554, l'conductor 555, the upper contacts of cani 361 and thence to ground over the circuit previously traced.

vFinal tens selection.

`lilith sequence switch 400 in position 18, l the fundamental.,circuit Apreviously `traced is established through the Winding ot' the control relay (not shown) of final selector 190 -andfthe windings of sender stepping relay 407. Relay 407, upon energizing, `prepares a circuiti-igor 1the N o. `1counting'relay426,

itbeing assumed that the. calling subscriber hassct the tens register T. in position 1. The

`circuit of relay 426 may be ltracedtroni battery 4through the Winding of relay v426, the arinature and baclcontactof the No. 1 counting relay'y 427, lead 475,' lead"649, Fig. 6, terniinal650ot banlr T, Wiper 651 con- `ductor 652, the right-hand contacts of Cain v418 andthence toground through the arinature contactlof steppingrelay 407 and the upper contact ot cani 413 17 to 18). yRelay v 426, upon energizing, locks up inthe Well- 4lrnoniiinanner through the Winding of the No. 1 counting relay427and duringrthe tens selection inoyeinent'ot the linal selector 1.90, the counting relays operate in succes .sion until Ithe No. 0 counting relay k429 energizes in-parallel Witlrrelay 409, whenV the fundamental circuit is opened to v arrest 4the `selective movement of the inalselector and vrelay-429 establishesa circuiti'or energizng relays 41l'and'436.

The circuit ot relays 411 and 436 ina-y be iso 'last numerical digit.

traced from battery through the windings of these relays, conductor 452, the upper lefthand and lower right-hand contacts of cam 451 (18), conductor 440, the inner righthand armature and back contact of relay 421, conductor 441 and thence to ground at the armature Contact of No. 0 counting relay 429. lRelay 436, upon energizing, closes a locking circuit for itself and for relay 411 which may be traced through the windings of these relays, the inner right-hand armature and front contact of relay 436 and thence over conductor 438 to ground at the upper contact of cam 338 (3 to 15). Relay 436, upon energizing, connects ground to conductor 345 for maintaining relay 145 at the district selector' energized after sequence switch 400 leaves position 18 and opens cam contact 430. Relay 411 at its outer righthand Varmature and front contact establishes a circuit which may be traced over conductor 453 and through the windings of relays 454 and 404 to battery. A circuit is now established for advancing sequence switch 400 out of position 18 and into position 2, the energization of relays 411, 436, 454 and 404 being thus effective to change the circuits of the sender to operate with sequence switch 400 in its second revolution. The circuit for advancing sequence switch 400 may now be traced from battery through the magnet winding of switch 400, the upper left-hand contact of cam 439 (18 to 1), conductor 453, the outer left-hand armature and front contact of relay 454, conductor 455, the righthand contact of cam 430 (18 to 1), and thence to ground on conductor 425.

Fz'nal emits selection.

`With sequence switch 400 in position 2, the fundamental circuit extending from the control relay of the inal selector 190 through the winding of the sender stepping relay 407 may be traced in part from brush 151 'over the circuit previously traced to conductor 33'!" the left-hand winding of relay 457, the left-hand armature and front contact of relay 404, the upper left-hand contact of cam 456 (2), conductor 406, the windings of sender stepping relay 407, conductor 408, the armature and back contact of relay 409, conductor 410, the inner lefthand armature and front contact of relay 411, the upper right-hand and lower lefthand contacts of cam 458 and thence over the circuit previously traced to brush 156 of the district selector 150.

Relay 407 energizes in this circuit and establishes a circuit for the No. 2 counting relay 414, it being assumed that the calling subscriber has set the units register U into position 2 in response to the dialing of the 414 may be traced from battery through the winding of relay 414, the armature and back The circuit of relayv contact of the No. 2 counting relay 415, lead 416, lead 653, Fig. 6 bank terminal 654 of bank U3, wiper 655, conductor 656, the righthand armature and back contact of wipe-out relay 364, conductor 365, the contacts ot' cam 458, conductor 459, the inner right-hand armature and front Contact of relay 411, conductor 420 and thence as previously traced through the armature contact of stepping relay 407, to ground at the upper conl tact of cam 413 (1 to 2). Counting relay 414 in the well-known manner locks up through the winding of the ilo. 2 counting relay 415 and during the units selection movement of the final selector 190, the counting relays operate and lock up in succession until thc No. 0 counting relay 429 energizes in parallel with relay 409, when the fundamental circuit is opened to arrest the selective movement of selector 190 and the sequence switch 400 is advanced into position 4. The circuit of sequence switch 400 may be traced from battery through the magnet winding of switch 400, the upper right-hand contact of cam 439 (2), the left-hand armature and front Contact of relay 436, conductor 440, conductor 441, thence to ground at the armature contact of the No. 0 counting relay 429.

Since no stations digits have been dialed by the' calling subscriber the No. 0 counting relay 429 remains locked to cause sequence switch 400 to advance directly from position 2 into position 10. The locking circuit of relay 429 may be traced from battery through the windings of relay 428 and 429, the contact of cam 460 (3 to 8), the outer left-hand armature and front contact of relay 454, conductor 455, the upper righthand and lower left-hand contacts of cam 451 (3 to 8), conductor 461, conductor 551, the right-hand contacts of class switch cam 361, conductor 362, the upper contact of cam 450 (2 to 10), conductor 402, the left-hand armature and front contact of relay 329, conductor 331 and thence to ground at the outer left-hand armature and front contact of relay Talking select/071.

Following units selection the sequence switch ofthe incoming selector is advanced to reverse the direction of current flow over the fundamental circuit in the manner fully described in the Patent No. 1,505,171 to F. A. Stearn, issued Aug. 19, 1924, hereinbefore referred to and with the sender sequence switch 400 in position 10, both the sender stepping relay 407 and polarized overflow relay 457 energize, Relay 4.57 energizes at this time since its two windings operate cumulatively, its right-hand winding being energized over a circuit extending over conductor 463, to ground on conductor 425 through the lower left-hand contact of 

